Grade 7
  1. Introduction to Chemistry  1.1. What is Chemistry?  1.2. Importance of chemistry in daily life  1.3. Branches of chemistry  1.4. Scientific Method in Chemistry  1.5. Laboratory Safety Rules and Precautions  1.6. Common Laboratory Equipment and Their Uses  1.7. Units of measurement in chemistry
  2. Matter and its properties  2.1. Definition of Matter  2.2. Classification of matter  2.3. Properties of matter  2.3.1. Physical properties  2.3.2. Chemical properties  2.4. States of matter  2.4.1. Solid state  2.4.2. Fluid state  2.4.3. Gaseous state  2.4.4. Plasma and Bose–Einstein condensates  2.5. Changes in the states of matter  2.5.1. Melting and freezing  2.5.2. Evaporation and Condensation  2.5.3. Sublimation and deposition  2.6. Density and its applications  2.7. Diffusion and its importance
  3. Elements, Compounds, and Mixtures  3.1. Definition of the element  3.2. Classification of elements  3.3. Metals, Nonmetals and Metalloids  3.4. Noble gases and their properties  3.5. Introduction to the Periodic Table  3.6. Definition of Compound  3.7. Properties of Compounds  3.8. Introduction to Chemical Formulas  3.9. Definition of Mixture  3.10. Types of mixtures  3.10.1. Homogeneous mixture  3.10.2. Heterogeneous mixtures  3.11. Difference Between Compounds and Mixtures  3.12. Solutions, Colloids and Suspensions
  4. Separation of mixtures  4.1. Need for separation of mixtures  4.2. Separation methods  4.2.1. Filtration  4.2.2. Sedimentation and decantation  4.2.3. Evaporation  4.2.4. Crystallization  4.2.5. Distillation  4.2.6. Chromatography  4.2.7. Magnetic Separation  4.2.8. Centrifugation
  5. Atomic Structure  5.1. Introduction to Atoms  5.2. Structure of the atom  5.2.1. Nucleus and electron cloud  5.3. Subatomic particles  5.3.1. Proton  5.3.2. Neutron  5.3.3. Electrons  5.4. Atomic number and mass number  5.5. Isotopes and their uses  5.6. Ions and ion formation
  6. Periodic table  6.1. Introduction to the Periodic Table  6.2. Groups and periods  6.3. Trends in the Periodic Table  6.3.1. Atomic Size  6.3.2. Metallic and non-metallic character  6.3.3. Electronegativity  6.3.4. Reactivity of the elements  6.4. Alkali metals and their properties
  7. Chemical bond  7.1. Why do atoms form bonds?  7.2. Types of chemical bonds  7.2.1. Ionic bond  7.2.2. Covalent bond  7.2.3. Metal Bond  7.3. Properties of Ionic and Covalent Compounds  7.4. Intermolecular forces
  8. Chemical reactions  8.1. Introduction to Chemical Reactions  8.2. Signs of a chemical reaction  8.3. Types of Chemical Reactions  8.3.1. Combination Reactions  8.3.2. Decomposition reactions  8.3.3. Displacement reactions  8.3.4. Double displacement reactions  8.3.5. Combustion reactions  8.4. Law of conservation of mass  8.5. Balancing simple chemical equations
  9. Acids, Bases and Salts  9.1. Definition of Acid and Base  9.2. Properties of Acids  9.3. Properties of bases  9.4. pH Scale and Indicators  9.5. Neutralization reactions  9.6. Common Acids and Bases in Everyday Life  9.7. Preparation and use of salts  9.8. Strong and weak acids and bases
  10. Solutions and Solubility  10.1. Definition of Solution  10.2. Components of the solution  10.2.1. Solvent  10.2.2. solute  10.3. Factors Affecting Solubility  10.4. Concentration of solutions  10.5. Saturated and unsaturated solutions  10.6. Colloids and suspensions  10.7. Solubility curve and its interpretation
  11. Air and atmosphere  11.1. Composition of air  11.2. Properties of gases in the air  11.3. Importance of Oxygen and Carbon Dioxide  11.4. Air pollution and its effects  11.5. Greenhouse effect and global warming  11.6. Ways to reduce air pollution  11.7. Ozone layer and its importance
  12. Water and its importance  12.1. Properties of Water  12.2. Water as the universal solvent  12.3. Importance of water for life  12.4. Water pollution and its effects  12.5. Water Purification  12.5.1. Filtration  12.5.2. boil  12.5.3. Chlorination in water purification  12.5.4. reverse osmosis  12.6. Hard and soft water  12.7. Water cycle and its importance
  13. Fuel and energy  13.1. Types of fuel  13.1.1. Fossil fuels  13.1.2. Renewable energy sources  13.2. Combustion and energy release  13.3. Global warming and its effects  13.4. Alternative sources of energy  13.5. Ways to conserve energy
  14. Metals and Nonmetals  14.1. Physical and chemical properties of metals  14.2. Physical and Chemical Properties of Non-Metals  14.3. Difference Between Metals and Nonmetals  14.4. Uses of metals and nonmetals  14.5. Corrosion of metals and its prevention  14.6. Alloys and their importance
  15. Plastics and polymers  15.1. Natural and synthetic polymers  15.2. Properties of plastics  15.3. Biodegradable and Non-Biodegradable Plastics  15.4. Environmental impact of plastic  15.5. Recycling and waste management in plastics and polymers  15.6. Daily Uses of Polymers
  16. Introduction to Organic Chemistry  16.1. Basic definitions of organic chemistry  16.2. Carbon Compounds in Daily Life  16.3. Hydrocarbons  16.4. Simple functional groups (alcohols and carboxylic acids)  16.5. Importance of organic compounds in industry

Grade 7 → Acids, Bases and Salts ↓


Preparation and use of salts


In chemistry, the term "salt" refers to a class of compounds that form when acids and bases react together. They play important roles in both natural processes and industrial applications. The topic of salts is essential to understanding chemical reactions.

What are salts?

Salts are ionic compounds composed of cations (positively charged ions) and anions (negatively charged ions), making them neutral overall. The most common and well-known salt is sodium chloride (NaCl), which is widely used as table salt.

Basic properties of salts

  • Salts are usually solid and crystalline at room temperature.
  • Most salts are soluble in water.
  • The colour of salts varies depending on their components.
  • They usually conduct electricity when dissolved in water, because of the movement of ions.

Preparation of salts

There are several methods of preparing salt depending on the type of salt and its intended use. Below are the main methods:

1. Neutralization reaction

The most common method of forming salts is through a reaction between an acid and a base. This process is called neutralization.

HCl (aq) + NaOH (aq) → NaCl (aq) + H 2 O (l)

In this reaction, hydrochloric acid (HCl) reacts with sodium hydroxide (NaOH) to form sodium chloride (NaCl) and water. Here's a visual example:

HCl NaOH sodium chloride H2O ,

2. Reaction of acid with metal

Salts can also be formed by the reaction of an acid with a metal. For example, when zinc reacts with hydrochloric acid, zinc chloride and hydrogen gas are formed:

Zn (s) + 2 HCl (aq) → ZnCl 2 (aq) + H 2 (g)

3. Reaction of an acid with a metal oxide

An acid can also react with metal oxides to form salts and water. For example, copper (II) oxide reacts with sulfuric acid to form copper (II) sulfate:

CuO (s) + H 2 SO 4 (aq) → CuSO 4 (aq) + H 2 O (l)

4. Reaction of an acid with a metal carbonate

When an acid reacts with a metal carbonate, salt, water, and carbon dioxide gas are formed. For example, calcium carbonate reacts with hydrochloric acid:

CaCO 3 (s) + 2 HCl (aq) → CaCl 2 (aq) + H 2 O (l) + CO 2 (g)

Uses of salts

Salts are incredibly versatile and are used in a variety of applications in everyday life and industries. Here are some examples:

1. Sodium chloride (NaCl)

  • Culinary uses: It is the most common salt used in food seasoning and preservation.
  • De-icing: It is widely used to melt ice on roads in winter.
    sodium chloride Used in food and de-icing

2. Calcium carbonate (CaCO 3)

  • Construction: Used in the production of cement and lime.
  • Medical use: An ingredient in antacid tablets for relief of heartburn.

3. Baking soda (sodium bicarbonate, NaHCO 3)

  • Baking: Acts as a leavening agent to help dough rise.
  • Cleaning: Used as a natural cleaner and deodorant for the home.

4. Epsom salt (magnesium sulfate, MgSO4)

  • Gardening: Provides magnesium to plants, thereby promoting growth.
  • Bath product: Used in the bath to relax muscles and relax the body.

Conclusion

Salts are an integral part of many natural and industrial processes. They can be prepared through a variety of reactions involving acids, bases, metals and metal oxides or carbonates. Each type of salt has its own specific uses that are beneficial in everyday life and industrial applications. Understanding their preparation and use helps us understand the role of chemistry in everyday life.


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Preparation and use of salts

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